Optical devices are usable for concentrating light towards a target region or a target element located in the target region. It is generally desired to achieve a high amount of light guided by the optical device to be incident on the target element.
In the following, reference is made to a luminescent optical device usable in the technical area of photovoltaic technology without loss of generality.
Such a luminescent optical device may be configured for collecting sunlight along an extension of the optical device, and for guiding the collected sunlight to a photovoltaic element which usually comprises small dimensions. Thus, the required area of the photovoltaic element on which the light is incident may have to be kept low, in order to decrease manufacturing costs for the photovoltaic element.
WO 2011/012545 A1 describes a luminescent optical device for use in a solar cell system. The luminescent optical device comprises a lens structure attached to a top surface of a substantially planar waveguide element. The lens structure comprises a plurality of lenses arranged side-by-side on the waveguide element, and a first wavelength selective mirror layer facing the waveguide element. A luminescent structure comprising luminescent domains is provided on a flat lower surface of the substantially planar waveguide. A second wavelength selective mirror layer is provided on the flat lower surface and the luminescent domains, with the luminescent domains being arranged in between the waveguide and the second wavelength selective mirror layer. In operation of the luminescent optical device, sunlight is incident on the luminescent optical device, and is converted to light of another wavelength by the luminescent domains. The converted light is guided by the waveguide element towards a photovoltaic cell of the solar cell system, and is reflected at the first and second wavelength selective mirrors.